My best friend stayed the night in a stranger’s house in Key West. She had a terrible nightmare that she and another woman were dressed in period clothing and were mopping up a lake of blood. She awoke shaken and feeling sick. The owner of the house then told her that a gruesome and bloody murder had taken place in that exact location.

There's a possibility all of these stories are the result of drugs, mental illness, physical illness, stress, sleep paralysis, dreams, or natural phenomena misidentified. That all of these stories are the result of the story teller lying or exaggerating.
But out of all the hundreds of stories here there is also the very real possibility that perhaps one is the absolute truth, that one has no other possible explanation other than the supernatural.
The question is, which story is it and what would that suggest about the universe.